• An essential fatty acid (EFA) deficiency developed in a 19-year-old man who was being maintained on a long-term regimen of fat-free, intravenous hyperalimentation fluids. The EFA deficiency was reversed after 21 days by daily, topical application of linoleic acid to the patient's skin. The ratio of eicosatrienoic acid (20:3, n-9) to eicosatetraenoic acid (20:4, n-6) decreased to normal levels in the skin and serum with clinical improvement of the EFA deficiency syndrome. The cutaneous manifestations (scalp dermatitis, alopecia, and depigmentation of hair) were reversed with continued, topical application of safflower oil, which contains 60% to 70% linoleic acid.